override property definition in node type definition?

[sam lee]

Hey, I have this:

<example = 'http://www.example.com/1.0'>
[example:Base] > nt:base
    - * (undefined) multiple
    - * (undefined)

example:Base nodes can have all kinds of properties named anyway.

[example:Derived] > example:Base

In example:Derived, can I override so that only certain properties are
valid?

I want to mask some of property definitions of example:Base:
    - * (undefined) multiple
    - * (undefined)


Thanks.
Sam